basic README

README.md

@@ -0,0 +1,120 @@
+# lceb - a Countdown solver in C.
+
+`lceb` will find the best solutions(s) for the Numbers part of the
+https://en.wikipedia.org/wiki/Countdown_(game_show)#Numbers_round
+Coundown game ("_Le compte est Bon_" in French).
+
+## Get the source
+
+``` text
+git clone https://git.bodiccea.tk/bruno/Le-Compte-est-Bon.git
+
+```
+
+## Build
+
+To display mode debug information, you may first enable some DEBUG flags in the `Makefile`.
+
+To build the binaries just run:
+``` shellsession
+$ make lceb
+```
+
+## Usage
+
+### basic usage and output
+
+```console
+$ ./lceb 2 7 1 7 8 8
+timer started...
+mem: allocating operators working area (5 bytes)
+new_stack: allocating 1024 stacks
+get_node: allocating 1024 new nodes - total nodes=1024
+target assigned (2).
+SIGINT armed.
+stacks          :             30
+ops combinations:            256
+trees           :             14
+max evaluations :        537,600
+Le compte est bon: 5 solutions with 2 ops (1st after 0.00030 secs).
+1 8 7 - +
+1 8 8 / +
+1 7 7 / +
+1 8 + 7 -
+8 7 1 - -
+Total time elapsed: 0.01327 secs, nodes/leaves evaluated:401,817/397,973
+```
+`lceb` takes at least 3 arguments: target number (the one to find), and from 2 to 6 use-able numbers.
+The solutions are displayed by default in RPN notation (here `1 8 7 - +` means `(8-7)+1`).
+
+### options
+
+You can see the available options with `lceb -h`:
+```console
+$ ./lceb -h
+usage: ./lceb [options] target n1 n2 [...n6]
+Countdown game solver.
+  -1: Show only one solution (immediate stop when exact solution found
+  -c: Show solutions timer
+  -d TYPE: Solutions display type. TYPE can be:
+           r: RPN (default)
+           p: Polish
+           l: Lisp (binary operators)
+           i: Infix (full parentheses)
+           d: Suitable for dc(1) input
+           t: Tree
+  -i: Show intermediate solutions
+  -s: Do not show summary (time, nodes evaluated)
+  -t: Use less trees (Wedderburn–Etherington instead of Catalan)
+  -T TIMER: Will stop after TIMER 1/10th seconds
+  -h: This help
+```
+
+### the -t option
+
+Using `-t` gives a large performance boost. Compare the two output below :
+
+```console
+$ ./lceb -di -c 997 4 8 25 2 5 3
+timer started...
+mem: allocating operators working area (6 bytes)
+new_stack: allocating 1024 stacks
+get_node: allocating 1024 new nodes - total nodes=1024
+target assigned (997).
+SIGINT armed.
+stacks          :            720
+ops combinations:          1,024
+trees           :             42
+max evaluations :    185,794,560
+get_node: allocating 1024 new nodes - total nodes=2048
+get_node: allocating 1024 new nodes - total nodes=3072
+get_node: allocating 1024 new nodes - total nodes=4096
+get_node: allocating 1024 new nodes - total nodes=5120
+Le compte est bon: 3 solutions with 3 ops (1st after 0.00841 secs).
+0.00841 secs: (((5 * 8) * 25) - 3)
+0.00841 secs: (((5 * 25) * 8) - 3)
+0.00841 secs: (((8 * 25) * 5) - 3)
+Total time elapsed: 3.40713 secs, nodes/leaves evaluated:138,979,332/132,474,697
+```
+
+```console
+$ ./lceb -di -t -c 997 4 8 25 2 5 3
+timer started...
+mem: allocating operators working area (6 bytes)
+new_stack: allocating 1024 stacks
+get_node: allocating 1024 new nodes - total nodes=1024
+target assigned (997).
+SIGINT armed.
+stacks          :            720
+ops combinations:          1,024
+trees           :              6
+max evaluations :     26,542,080
+get_node: allocating 1024 new nodes - total nodes=2048
+Le compte est bon: 3 solutions with 3 ops (1st after 0.15392 secs).
+0.15392 secs: (((5 * 8) * 25) - 3)
+0.15392 secs: (((5 * 25) * 8) - 3)
+0.15393 secs: (((8 * 25) * 5) - 3)
+Total time elapsed: 0.47460 secs, nodes/leaves evaluated:18,793,369/18,650,735
+```
+
+It should be noted that having general performance improvement does not mean that the first solution will be found sooner.

best.c

@@ -12,7 +12,7 @@ static int bestops=MAXINT;
 
 static BEST bests[1024*10];        /* TODO: should be dynamic */
 static int nbests=0;
-extern int displaytimer;
+extern int displaytimer, firstonly;
 int displayintermediate=0;
 int displaytype=0;
 
@@ -120,12 +120,16 @@ void print_best(node, values, pops, depth)
 
 void print_bests()
 {
-    int i=0;
-    printf("BEST SOLUTION: res=%d diff=%d ops=%d ", bests[i].res, bestdiff, bestops);
+    int i=0, j=firstonly? 1: nbests;
+    if (bestdiff==0) {
+        printf("Le compte est bon: %d solutions with %d ops ", nbests, bestops);
+    } else {
+        printf("Found %d results with difference %d and %d ops ", nbests, bestdiff, bestops);
+    }
     //if (displaytimer)
-    printf("found after %.5f secs.", get_timer(bests[i].timer));
+    printf("(1st after %.5f secs).", get_timer(bests[i].timer));
     putchar('\n');
-    for (i=0; i<nbests; ++i) {
+    for (i=0; i<j; ++i) {
         //print_best(bests[i].root, bests[i].values, bests[i].oper, 0);
         //printf("%5d =", bests[i].res);
         if (displaytimer)

eval.c

@@ -82,7 +82,7 @@ int eval_node(node, depth, pvals, pops, ncalcs)
                 if (val1<val2) {
                     NODE *tmp=node->left;
 #                   ifdef DEBUG_EVAL2
-                    printf("eval: Sub: swapping val1=%d val2=%d\n", val1, val2);
+                    printf("eval: Div: swapping val1=%d val2=%d\n", val1, val2);
 #                   endif
                     node->left=node->right;
                     node->right=tmp;
@@ -115,7 +115,7 @@ int eval_node(node, depth, pvals, pops, ncalcs)
         }
     }
     if (sigint_received) {
-        print_bests();
+        print_results();
         exit(1);
     }
 

lceb.c

@@ -20,6 +20,7 @@
 
 static char *cmd;
 static int treetype=TREE_CATALAN;
+static int maxmillisecs=0;
 extern int displaytimer, displayintermediate, displaytype, firstonly;
 int displaysummary=1;
 
@@ -42,7 +43,7 @@ void help()
 {
     usage();
     fprintf(stderr, "Countdown game solver.\n");
-    fprintf(stderr, "  -1: Stops immediately when one solution is found\n");
+    fprintf(stderr, "  -1: Show only one solution (immediate stop when exact solution found\n");
     fprintf(stderr, "  -c: Show solutions timer\n");
     fprintf(stderr, "  -d TYPE: Solutions display type. TYPE can be:\n");
     fprintf(stderr, "           r: RPN (default)\n");
@@ -54,6 +55,7 @@ void help()
     fprintf(stderr, "  -i: Show intermediate solutions\n");
     fprintf(stderr, "  -s: Do not show summary (time, nodes evaluated)\n");
     fprintf(stderr, "  -t: Use less trees (Wedderburn–Etherington instead of Catalan)\n");
+    fprintf(stderr, "  -T TIMER: Will stop after TIMER 1/10th seconds\n");
     fprintf(stderr, "  -h: This help\n");
 }
 
@@ -75,7 +77,7 @@ int main(ac, av)
     TREE *tree;
     char intarray[1024];
     char *comb;
-    char *options="1thcisd:";
+    char *options="1thcisd:T:";
     int option;
 #   ifdef DEBUG_MAINLOOP
     int eval;
@@ -124,6 +126,9 @@ int main(ac, av)
             case 's':
                 displaysummary=0;
                 break;
+            case 'T':
+                maxmillisecs=atoi(optarg)*100;
+                break;
             case 't':
                 treetype=TREE_WEDDERBURN;
                 break;
@@ -143,6 +148,8 @@ int main(ac, av)
     }
     setlocale(LC_ALL, "");                        /* to use "%'d" in printf */
     start_timer();
+    if (maxmillisecs)
+        set_alarm(maxmillisecs);
     target=atoi(av[optind]);
     stacksize=ac-optind-1;
     nops=stacksize-1;

lceb.h

@@ -7,6 +7,9 @@
 #define MAX(a,b)        (((a)>(b))?(a):(b))
 #define ABS(a)          (((a)<0)?-(a):(a))
 
+#define NANOSEC    1000000000.0
+#define MILLISEC   1000
+
 typedef enum {
     Nop='N',
     Add='+',
@@ -71,6 +74,7 @@ extern void print_results();
 /* signal.c */
 extern void set_intr();
 extern int stopped();
+extern void set_alarm(int ms);
 
 /* tree.c */
 extern NODE *get_node();

signal.c

@@ -1,11 +1,15 @@
 #include <stdio.h>
 #include <signal.h>
+#include <sys/time.h>
+#include <string.h>
+#include "lceb.h"
 
 int sigint_received=0;
 
-static void stopall()
+static void stopall(signum)
+    int signum;
 {
-    printf("SIGINT RECEIVED: aborting eval\n");
+    printf("SIGNAL %d RECEIVED: aborting eval\n", signum);
     sigint_received=1;
 }
 
@@ -20,14 +24,35 @@ void set_intr()
 
     sig.sa_handler = stopall;
     sigemptyset(&sig.sa_mask);
-    //sigaddset(&new.sa_mask, SIGINT);
-    //sigaddset(&new.sa_mask, SIGALRM);
     sig.sa_flags = 0;
-    //sigaction(SIGINT, NULL, &old);
-    //if (old_action.sa_handler != SIG_IGN) {
     sigaction(SIGINT, &sig, NULL);
     sigaction(SIGALRM, &sig, NULL);
 #   ifdef DEBUG
-    printf("SIGINT and SIGALRM armed.\n");
+    printf("SIGINT armed.\n");
 #   endif
 }
+
+void set_alarm(ms)
+    int ms;
+{
+    struct sigaction sa;
+    struct itimerval timer;
+
+    /* Install timer_handler as the signal handler for SIGVTALRM. */
+    memset (&sa, 0, sizeof (sa));
+    sa.sa_handler = stopall;
+    sigaction (SIGUSR1, &sa, NULL);
+
+    timer.it_value.tv_sec = ms/1000;
+    timer.it_value.tv_usec = (ms%1000)*1000;
+#   ifdef DEBUG
+    printf("alarm clock set to %.2f secs.\n",
+           timer.it_value.tv_sec + timer.it_value.tv_usec / 1000000.);
+#   endif
+    /* ... and every 250 msec after that. */
+    timer.it_interval.tv_sec = 0;
+    timer.it_interval.tv_usec = 0;
+    /* Start a virtual timer. It counts down whenever this process is executing. */
+    setitimer (ITIMER_REAL, &timer, NULL);
+
+}

timer.c

@@ -1,9 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
-
-#define NANOSEC    1000000000.0
-#define MILLISEC   1000
+#include "lceb.h"
 
 int displaytimer=0;
 static  struct timespec start;